<?php

namespace exchange;
/*------------------------------------------------------ */
//-- 该类用于与数据库数据进行交换
/*------------------------------------------------------ */
class Exchange
{
    public $model;
    public $id;
    public $name;
    public $error_msg;

    /**
     * 构造函数
     *
     * @access  public
     * @param   string       $model       数据库表名
     * @param   string       $id          数据表主键字段名
     * @param   string       $name        数据表重要段名
     *
     * @return void
     */
    public function __construct($model, $id, $name){
       $this->model     = $model;
       $this->id        = $id;
       $this->name      = $name;
       $this->error_msg = '';
     }

    /**
     * 判断表中某字段是否重复，若重复则中止程序，并给出错误信息
     *
     * @access  public
     * @param   string  $col    字段名
     * @param   string  $name   字段值
     * @param   integer $id
     *
     * @return void
     */
    public function is_only($col, $name, $id = 0, $where='')
    {
        $sql   = "$col = '$name'";
        $sql  .= empty($id) ? '' : ' AND ' . $this->id . " <> '$id'";
        $sql  .= empty($where) ? '' : ' AND ' .$where;

        $count = $this->model->where($sql)->count();
        return ($count == 0);
    }

    /**
     * 返回指定名称记录再数据表中记录个数
     *
     * @access  public
     * @param   string      $col        字段名
     * @param   string      $name       字段内容
     *
     * @return   int        记录个数
     */
    function num($col, $name, $id = 0)
    {
        $sql = 'SELECT COUNT(*) FROM ' .$this->model. " WHERE $col = '$name'";
        $sql .= empty($id) ? '' : ' AND '. $this->id ." != '$id' ";

        return $this->db->getOne($sql);
    }

    /**
     * 编辑某个字段
     *
     * @access  public
     * @param   string/array      $data        要更新集合如" col = '$name', value = '$value'"
     * @param   int         $id         要更新的记录编号
     *
     * @return bool     成功或失败
     */
    function edit($set, $id)
    {
        if( !is_array($set) ){
            $data = array();
            $set  = explode(',', $set);
            foreach ($set as $k => $v) {
                $v = str_replace("'",'',$v);
                $v = str_replace('"','',$v);
                $v = explode('=', $v);
                $data[$v[0]] = $v[1];
            }
        }else {
            $data = $set;
        }

        $res = $this->model->where("$this->id = '$id'")->save($data);

        if ($res)
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    /**
     * 取得某个字段的值
     *
     * @access  public
     * @param   int     $id     记录编号
     * @param   string  $id     字段名
     *
     * @return string   取出的数据
     */
    function get_name($id, $name = '')
    {
        if (empty($name))
        {
            $name = $this->name;
        }

        $sql = "SELECT `$name` FROM " . $this->model . " WHERE $this->id = '$id'";

        $val = $this->model->where("$this->id = '$id'")->getField("$name");

        // return $this->db->getOne($sql);
        return $val;
    }

    /**
     * 删除条记录
     *
     * @access  public
     * @param   int         $id         记录编号
     *
     * @return bool
     */
    function drop($id)
    {
        $sql = 'DELETE FROM ' . $this->model . " WHERE $this->id = '$id'";

        return $this->db->query($sql);
    }
}

?>
